1. Field
This invention relates to musical apparatus. In particular, the invention pertains to a melody analyzer for analyzing a melody for tonality and a melody harmonizer for harmonizing the melody using the results of the melody analysis.
2. Description of the Prior Art
A melody analyzer which determines a key of a melody is known. Such a melody analyzer is often used in an automatic accompaniment apparatus which provides an automatic accompaniment to a melody. A typical prior art melody analyzer matches the set of notes of a melody against a pitch class set (PCS) of a scale while changing its tone from a pitch class to another to determine a key of the melody. Another prior art melody analyzer utilizes the last note of a melody for key determination.
However, either prior art melody analyzer operates based on the premise that a given melody does not include any modulation (change of key). Thus, none of the prior art melody analyzers can provide satisfactory tonality analysis of a melody having modulation in its course since a wrong key is determined for a portion of such a melody.
A melody harmonizer for harmonizing a melody is known. The prior art melody harmonizer divides a melody into a plurality of segments having the same length (e.g., one or half bar) based on the premise that each segment is harmonized by a single chord. The prior art melody harmonizer determines a chord of each segment in accordance with a chord determining algorithm using pitch contents of the segment and/or a chord assigned to a preceding segment.
Thus, the resultant chord progression involves unnaturalness peculiar to the chord determining algorithm. Further, the play of an accompaniment using such chord progression sounds monotonous since a chord or harmony changes regularly per same length of time.
An automatic accompaniment apparatus is known which harmonizes a melody and automatically plays an accompaniment based on the results of harmonization and preselected accompaniment style.
The prior art apparatus, however, has no capability of anlyzing a melody for its style. Instead, it merely uses the preselected accompaniment style information to retrieve, from an accompaniment pattern memory, an accompaniment pattern of that preselected accompaniment style. This results in a monotonous accompaniment.